Conventional platform structures for manufacturing a scaffold for use in tissue engineering are expected to be of a matrix structure with a high porosity to render it easy to carry and transplant cells into a patient's body. In this regard, a common manufacturing technique entails carrying out an additive manufacturing process (referring to Melchels F P W, Domingos M A N, Klein T J, et al. Additive manufacturing of tissues and organs. Prog Polym Sci 2012; 37:1079-1104.) The additive manufacturing technique falls into several categories, namely stereolithography (SLA), selective laser sintering (SLS), fused deposition manufacturing (FDM), and the like. FDM has a drawback, that is, thermal hydrolysis occurs to the materials for use in manufacturing of a scaffold for use in tissue engineering (see: Gross B C, Erkal J L, Lockwood S Y, et al. Evaluation of 3D printing and its potential impact on biotechnology and the chemical sciences. Anal Chem 2014; 86:3240-3253.) To overcome the aforesaid drawback, the related industrial sector developed a “pseudo-FDM” additive manufacturing technique (see: (1) Xiong Z, Yan Y, Wang S, et al. Fabrication of porous scaffolds for bone tissue engineering via low-temperature deposition. Scr Mater 2002; 46:771-776; (2) Yen H J, Tseng C S, Hsu S H, et al. Evaluation of chondrocyte growth in the highly porous scaffolds made by fused deposition manufacturing (FDM) filled with type II collagen. Biomed Microdevices 2009; 11:615-624; and (3) Yen H J, Hsu S H, Tseng C S, et al. Fabrication of precision scaffolds using liquid-frozen deposition manufacturing for cartilage tissue engineering. Tissue Engineering Part A 2009; 15: 965-975) for use in low-temperature manufacturing of a scaffold for use in tissue engineering.
A conventional method of manufacturing a scaffold for use in tissue engineering entails squeezing out a liquid material with horizontally and vertically movable nozzles such that the liquid material deposits on a fixed thermally conductive platform, and allowing the liquid material to freeze as soon as the liquid material comes into contact with the low-temperature thermally conductive platform. Therefore, a scaffold for use in tissue engineering is formed. Incoming liquid material deposits on the frozen liquid material to form a tall scaffold for use in tissue engineering (referring to: (1) Liu C, Li Y, Zhang L, et al. Development of a novel low-temperature deposition machine using screw extrusion to fabricate poly(L-lactide-co-glycolide) acid scaffolds. Proc IMechE Part H: J Engineering in Medicine 2014; 228:593-606; (2) Liu L, Xiong Z, Yan Y, et al. Multinozzle low-temperature deposition system for construction of gradient tissue engineering scaffolds. J. Biomed. Mater. Res. B. 2008; 86B:254-263; (3) Kai H, Wang X, Madhukar K S, et al. Fabrication of a two-level tumor bone repair biomaterial based on a rapid prototyping technique. Biofabrication 2009; 1:1-7; (4) Pham C B, Leong K F, Lim T C, et al. Rapid freeze prototyping technique in bio-plotters for tissue scaffold fabrication. Rapid Prototyping Journal 2008; 14:246-253; (5) Kim G H, Ahn S H, Yoon H, et al. A cryogenic direct plotting system for fabrication of 3D collagen scaffolds for tissue engineering. J Mater Cham 2009; 19:8817-8823; and (6) Doiphode N D, Huang T, Leu M C et al. Freeze extrusion fabrication of 13-93 bioactive glass scaffolds for bone repair. J Mater Sci Mater Med 2011; 22:515-523).
With ambient temperature being higher than the temperature of the thermally conductive platform, the greater the required deposited amount of the liquid material, the more likely the liquid material is to be affected by the ambient temperature and thus less likely to freeze, thereby resulting in the deformation of the top portion of the manufactured scaffold for use in tissue engineering, thereby rendering useless the manufactured scaffold for use in tissue engineering. Hence, the conventional method fails to manufacture a tall scaffold, say, a scaffold taller than 1 cm; and the maximum height of the scaffold which can be manufactured by the conventional method varies from thermally conductive platform to thermally conductive platform. For example, some thermally conductive platforms are accountable for the deformation of the top portion of a scaffold which is 1 cm high. Furthermore, in addition to the deformation of the top portion of a scaffold thus manufactured, ambient temperature causes uneven internal structure of a scaffold thus manufactured.
Furthermore, putting the equipment required for manufacturing conventional scaffold s for use in tissue engineering in a low-temperature room or a low-temperature workshop incur costs.
In view of this, it is important to provide a platform structure conducive to the prevention of the deformation of the top portion of a tall scaffold for use in tissue engineering and the uniform distribution of the internal structure of the tall scaffold.